Data types in C/C++ are used in the declaration of all variables to limit the type of data that can be stored. As a result, data types are used to inform variables about the types of data they can store. When a variable is declared in C++, the compiler allocates memory for it based on the data type that it is declared with. Each sort of data necessitates a particular quantity of memory.

In C++, data types are separated into three categories:

• 1. Type of Primitive Data
• 2. Data Types Derived from Other Data(Derived data type)
• 3. User-Defined Data Types or Abstract Data Types

1. Primitive Data Types: These data types are built-in or preset data types that the user can declare variables with directly. For instance, int, char, float, bool, and so on. The following primitive data types are available in C++:

• Integer
• Character
• Floating Point Boolean
• Floating Points in Twos
• Wide Character
• Valueless or Void

2. Derived Data Types: Derived Data Types are data types that are derived from primitive or built-in datatypes.

There are four different varieties of these:

• Function
• Array
• Pointer
• Reference

3. User-Defined Data Types: These are data types that are defined by the user. As an example, in C++, defining a class or a structure. The following user-defined datatypes are available in C++:

• Class
• Structure
• Union
• Enumeration
  Defining a typedef DataType

4. Modifiers in Datatypes: Datatype modifiers are used with built-in data types to change the length of data a data type can carry, as the name implies.

• Signed
• Unsigned
• Short
• Long

Data Type	Size (in bytes)	Range
short int	2	-32,768 to 32,767
unsigned short int	2	0 to 65,535
unsigned int	4	0 to 4,294,967,295
int	4	-2,147,483,648 to 2,147,483,647
long int	4	-2,147,483,648 to 2,147,483,647
unsigned long int	8	0 to 4,294,967,295
long long int	8	-(2^63) to (2^63)-1
unsigned long long int	8	0 to 18,446,744,073,709,551,615
signed char	1	-128 to 127
unsigned char	1	0 to 255
float	4
double	8
long double	12
wchar_t	2 or 4	1 wide character

// C++ program to sizes of data types
#include<iostream>
using namespace std;

int main()
{
	cout << "Size of char : " << sizeof(char)
	<< " byte" << endl;
	cout << "Size of int : " << sizeof(int)
	<< " bytes" << endl;
	cout << "Size of short int : " << sizeof(short int)
	<< " bytes" << endl;
	cout << "Size of long int : " << sizeof(long int)
	<< " bytes" << endl;
	cout << "Size of signed long int : " << sizeof(signed long int)
	<< " bytes" << endl;
	cout << "Size of unsigned long int : " << sizeof(unsigned long int)
	<< " bytes" << endl;
	cout << "Size of float : " << sizeof(float)
	<< " bytes" <<endl;
	cout << "Size of double : " << sizeof(double)
	<< " bytes" << endl;
	cout << "Size of wchar_t : " << sizeof(wchar_t)
	<< " bytes" <<endl;
	
	return 0;
}

Output: 

Size of int : 4 bytes
Size of short int : 2 bytes
Size of long int : 8 bytes
Size of signed long int : 8 bytes
Size of unsigned long int : 8 bytes
Size of float : 4 bytes
Size of double : 8 bytes
Size of wchar_t : 4 bytes

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